Operating mechanism for electric circuit breakers



1954 H. N. SCHNEIDER ET AL OPERATING MECHANISM FOR ELECTRIC CIRCUITBREAKERS.

Filed Aug. 28, 1951 w A ll/I n I.. "m5 7 U Insulation inventors. HaroldN.Schneider,

Reed M.Anderson,

Their Attorney.

Patented June 8, 1954 OPERATING MECHANISM FOR ELECTRIC CIRCUIT BREAKERSHarold N. Schneider, Springfield, and Reed M. Anderson, Media, Pa.,assignors to General Electric Company, a corporation of New YorkApplication August 28, 1951, Serial No. 244,064

14 Claims. I.

This invention relates to .operating mechanisms for electric circuitbreakers and more particularly to a mechanism for supplying a controlledblast of gas to the contacts of a high voltage'circuit breaker of thegas blast type during the performance of circuit closing operations'bythe breaker.

A blast of gas such as high pressure air is commonly employed in gasblast circuit breakers to extinguish an are drawn between the breakercontacts during circuit opening operations. During circuit closingoperations of high voltage breakers, an arc may strike between thebreaker contacts while the contacts are still separated by a substantialdistance. Such arcs cause damage to the breaker contacts and maynecessitate frequent inspection and repair or replacement of the contactmembers resulting in undesirable outage time for the breaker. Thetendency for an arc to strike prematurely during circuit closingoperations can be controlled by supplying a blast of gas to the spacebetween and around the contacts. Since such a blast is not for thepurpose of extinguishing an are, as during circuit opening operations ofthe breaker, the magnitude of the blast need not be as great duringclosing of the breaker as is required during opening operations. In Viewof this fact it is possible to supply a controlled-blast of a lessermagnitude during closing operations then is required during openingoperations of the breaker and in this way the supply of pressure gas isnot needlessly wasted. This invention is concerned primarily with anarrangement whereby a limited blast of gas is supplied to.the breakercontacts while the breaker performing a circuit closing oper ation.

A principal object of this invention is to provide an improved operatingmechanismfor highvcltage gas blast circuit breakers wherein a blast ofgas is supplied to the breaker contacts both during opening and closingoperations of the breaker and wherein simple and reliable means.

are provided for limiting the magnitude of the blast during breakerclosing operations so as to conserve the supply of pressure gas.

In carrying out the invention in one form as applied to a single polecircuit breaker, a blast valve of the balanced type is moved to afullyopened position during opening operations of the breaker by onevalve operating means so as to supply an effective blast to extinguishthe arc during opening of the breaker, and during circuit closingoperations, theblast valve is moved to a partially-opened position byanother; valve;

Fig. 1 represents schematically a circuit breaker of the gas blasttypeand an operation mechanism therefor embodying theprinciples of theinvention, Fig. 2 represents an alternative arrangement of the parts,and in which Fig. 3 represents'a construction wherebythe breaker con---tacts are blasted directly from air supplied from the breaker operatingcylinder.

In the drawing the numeral I generally designates an interrupting unitcomprising one-pole of a gas blast circuit breaker. The supply ofpressure fluid to interrupting unit 5 is supplied through blast valve 2,which is under the control of opening control valve 3, from a source offluid pressure 4. Once the circuit controlled by the breaker has beeninterrupted by interrupter unit 5, a circuit isolating operation of thebreaker is accomplished-due to operation of fluid-actuated device 5 aswill be more fully explained.

Interrupter unit I comprises metallic structure 6 which supports fingercontacts 'I' biased by spring means S-into engagement with tubularcontact 9. The structure 55 is supported by an insulating casing Itwhich in turn is mounted upon the metallicbasesmember H. The specificconstruction of the unit l is more fully described and is claimed inapplication Serial No. 233,637- B'eatty, filed June 26, 1951, and aninterrupter of thegeneral type disclosed in'Fig. 1 is disclosed andbroadly claimed in application Serial No. 202',100--Beatty, filedDecember 21, 1950, now Patent No. 2,645697, dated July 14, 1953, both ofwhich applications are assigned to the assignee of this invention. Thefinger contacts l are separated from the tubular contact 9 by a plastergas supplied through valve 2 and through the space between the tubularcontact 9 and the casing it; Such a blast causes the contacts l to moveout of engagement with the tubular contact 9 against the bias of springmeans 8 and also extinguishes the arc. drawn between these contacts.This supplyof gas flows in the direction'of the-arrowsto atmosphere andis supplied to the valve-2; from the air receiver it through Since 3 theshort conduit 22. The terminals of the breaker are indicatedschematically by a line connected to member 3 and by another line insliding contact with the contact 9.

Blast valve 2 is of the balanced type and comprises a pair of disks 13mounted on a valve spindle on which is disposed a main operating pistoni6 and a valve restraining piston ll. The valve is biased toward theclosed position by spring means Hl. A conduit 18 interconnects openingcontrol valve 3 with the enclosing structure iii in which the mainoperating piston i3 is movable. As illustrated, opening control valve 3is of the electromagnetically-actuated type. Opening control valve 3, asis well known, could be responsive to an electric condition of thesystem controlled by the breaker l. Valve 3 also could be manuallyactuated or, of course, could be both manually and automaticallyoperable.

Full opening movement of blast valve 2 is accomplished when openingcontrol valve 3 is opened. Opening of the opening control valve 3supplies pressure fluid underneath the piston l3 and causes the valve 2to move to its fullyopened position. In this way a major blast issupplied to the interrupting unit I to separate the finger contacts 7from the tubular contact 9 and to extinguish an are drawn between thesecontacts. When blast valve 2 is reclosed due to the closing of controlvalve 3 and to the action of spring It, the contacts I will return tothe position illustrated due to the bias of springs 8.

After interruption of an are drawn between the contacts '3 and 9, asuitable isolating gap is esablished before the blast of fluid is shut01f. To this end the arrangement shown in the drawing is constructed sothat the tubular contact 8 can be drawn downwardly after or coincidentwith the completion of an interrupting operation. Contact 9 is connectedat its lower end to a vertical operating rod 29 of insulating materialwhich is pinned at 2| to a link 22 which in turn is pivoted at 23 to aguide link 24 mounted at fixed pivot 25. Operating crank 23 mounted forrotation about a fixed pivot 2'! is pinned at 23 to the link 22. Openingbias for contact 93 is supplied in the form of compressional spring 25which biases a transversely-disposed rod 33 to ward the right. Rod ispinned to crank 26 at 3 l. Spring 29 normally is ineffective to separatecontact 3 from finger contacts 1 due to the toggle constructioncomprising links 32 and 33 which are pinned together at 34. Rod 33 isconnected to link 33 through crank 35 pivotally mounted at the fixedpivot 36 and pinned at its upper extremity to rod 30 by pin 31 and atits lower end to link 33 by a pin 38. Link 32 is mounted on a fixedpivot 32a. With the toggle comprising links 32 and 33 in the overcenterposi tion indicated, the bias of spring 23 is inefiective to separatethe contacts. However, if the toggle is moved downwardly through deadcenter and beyond the spring 29 then imparts a rapid opening movement tothe contact 9 through 'rod 2!] and parts associated therewith. The lowerposition of rod 20 and of link 22 are indicated by dotted lines and thefull isolating stroke is indicated by the distance S. Opening movementof the parts is arrested when roller 38a on crank 23 engages buffer3817.

For the purpose of breaking the toggle com prising links 32 and 33, thefluid-actuated device 5 is arranged to respond to the opening of controlvalve 3 and the resulting operation of the fluid motor comprising piston16 and structure I9, to impart downward motion to break the toggle.

Fluid-actuated device 5 is provided with an enclosing cylinder 39 and anoperating piston 30. Thus when fluid pressure is supplied above piston40, downward motion will be imparted thereto so as to break the toggle32--33 whereupon spring 29 quickly opens the isolating contact 9.

Fluid pressure is supplied above the piston 40 by means of a conduit Mwhich connects to the enclosing structure It. Valve spindle I5 isprovided with an undercut portion 42 and fluid pressure is supplied fromopening control valve 3 to the structure l9 through a conduit 43. Thuswhen opening control valve 3 is opened, fluid pressure in conduit iswill cause piston I6 to move upwardly. Simultaneously, fluid pressuresupplied through conduit 43 passes through the structure l9 to theconduit 4| to operate piston 43 of fluid-actuated device 5 after theundercut portion 32 of the spindle l5 establishes communication betweenconduits 43 and 4|. Thus, it is impossible to supply fluid to the device5 to cause isolating movement of contact 9 unless the blast valve 2 hasbeen opened. This particular interlocking arrangement is more fullydisclosed and claimed in application Serial No. 233,542 Shores, filedJune 26, 1951, assigned to the assignee of the present invention and nowPatent No. 2,667,554.

As already mentioned, a full breaker opening stroke is completed withthe opening of the ison" lating contact 9; the cycle being terminated bythe timed reclosing of the closing valve 3 as through the operation ofan auxiliary switch actuated by some appropriate moving part during thedownward stroke of the piston All of the pneumatic operator 5. Thus,pressure below the blast valve piston i6 is relieved through theatmospheric vent of the closing control valve 3 so that the blast valve2 closes under the urge of its spring I 4, while pressure above themotor piston 43 is relieved, when the blast valve closes, through thevent to atmosphere in the structure it adjacent the undercut portion d2of the blast valve spindle; the opening spring 29 ensuring that a fullopening stroke is attained by the isolating contact 9.

Since the finger contacts i return to the position indicated due to theaction of biasing means 8 after the fluid blast is cut off, closure ofthe breaker is accomplished by imparting upward movement to the contact9. To this end. fluid pressure is supplied to the underside of piston 49of device 5 to cause upward movement thereof and movement of theoperating linkage against the bias of spring 29 to close the breaker.Fluid pressure is supplied to the lower portion of structure 39 by meansof breaker closing control valve 44 which, as indicated schematically onthe drawing, is of the electromagnetically-operated type. Valve M isconnected with cylinder through a conduit a and is constructed so as tovent the lower portion of cylinder 39 to atmosphere when closed. Fluidpressure is supplied to valve M through suitable means such as theconduit 44a.

In order to prevent an are from striking be tween contacts I and 9 ascontact 9 approaches the closed position, it is desirable to supply aminor blast of gas to the contacts. This minor blast is supplied byopening the valve 2 a partial distance only. In this way, the supply ofpressure fluid in air receiver t is not needlessly wasted.

For the purpose of imparting partial opening movement to blast valve 2 afluid motor comprising piston and a restraining means in the form ofpiston ii are provided in accordance with this invention. Fluid pressurefor this purpose is supplied to pistons ll and through conduits 4G andIll from an auxiliary valve comprising undercut portion 48 of a slidablemember 49 which is movable in accordance with movement of piston iiFluid pressure is supplied to conduit ts from the lower portion ofcylinder 39 through port 53 due to the establishment of communicationbetween port and conduit is as the undercut portion 48 of control member29 moves upwardly.

Fluid pressure supplied through conduit st bears against the uppersurface of restraining piston ii and through conduit 1 is caused to bearagainst the lower surface of piston to which is of larger diameter thanpiston ll. It will be observed that the travel B of piston ie is lessthan the travel A of piston it. Thus fluid pres sure supplied belowpiston 45 will impart upward movement to valve stem iii to force valve 2to open partially. Valve 2, being provided with the two disks !3, is ofthe balanced type. Thus the momentum of the parts, being sufficient toovercome the force of spring M, would cause the valve to open fully onceit is partially opened by piston 35. According to the invention, thepiston I! is arranged to exert a downward force on the valve spindle itso as to maintain the valve 2 in a partially-opened position asdetermined by the position of piston :35 after that piston completes itsupward travel. Furthermore, piston ll causes a slower opening of thevalve than when the valve is opened by piston it during opening of thebreaker.

It will be understood that it is within the purview of this invention tosegregate the control of the supply of fluid to piston ll from thecontrol member comprising the undercut portion 58 of control member d9.To this end a conduit could be connected directly from closing valve 44to the space above piston I? as indicated by conduit 5i in Fig. 2. If aconduit such as M is utilized, the conduits 45 and 4'! would beeliminated, and in. their place would be substituted the conduit 52connected directly to the space underneath piston 45 as is indicated inFig. 2. Thus pressure would be established above piston ll before theestablishment of pressure below the piston in the arrangement shown inFig. 2.

Partial opening movement of blast valve 2 during a circuit breakerclosing operation could be accomplished by a piston such as 35 and therestraining action to prevent movement of the valve 2 to therully-opened position could be achieved or supplemented by means of aport 565- shown in Fig. l which would establish communication betweenconduit [2 and the upper surface of piston once the blast valve 2 hadopened partially, and the pressure exerted on piston it would beanalogous to the pressure exerted on the upper surface of piston ll.While the construction embodying the port it is deemed within thepurview of this invention,'the arrangement utilizing piston ii isregarded as a preferable embodiment of the invention.

It will also be understood that the valve 2 could be restrained in itspartially-opened position after having been moved. thereto by the pistonii; by bufiing means in the form of the spring 55. Spring 55 wouldsupplement the action of biasing spring l4 and would retain the valve ina partially-opened position after the piston 45 had completed its fullstroke. It will be understood that spring 55 would be constructed so asnot to prevent the full opening movement of valve '2 during a circuitbreaker opening operation, the upward force of piston it beingsuificient to compress buffer 55 enough to allow full opening movementof valve 2. Bufier 55 could be used as supplementary to, or in lieu of,arrangements using piston 11 or port 56.

For certain applications of gas blast breakers, a sufficient blast forclosing operations of the breaker might be derived directly from thelower portion of fluid-actuated device 5 as indicated in Fig. 3. To thisend a conduit such as that indicated at 53 could be directly connectedbetween the lower portion of cylinder 3e and the space within the basemember H. In such a construction, the blast valve 2 would not beoperated during closing operations of the breaker and the buffer 55would merely arrest the up ward movement of the blast valve duringbreaker opening operations.

While we have shown and described certain embodiments of the invention,it will be understood that we do not wish to be limited to the specificarrangements disclosed and intend in the appended claims to cover allsuch changes and modifications as fall within the true spirit and scopeor this invention.

' What we claim as new and desire to secure by Letters Patent of theUnited States is:

l. In combination, a blast valve of the calanced type, means urging saidblast valve toward closed position, a fluid motor movable independentlyof said blast valve and engageable therewith for moving said blast valvefrom a closed to a partially opened position, means including a controlvalve for supplying pressure fluid to said motor to cause operationthereof, restraining means including a piston arranged to move with saidblast valve, and means for supplying pressure fluid to a surface of saidpiston coincident with the operation of said fluid motor, the forceexerted on said blast valve by said piston being in opposition to theforce produced by the pressure fluid supplied to said motor so as toprevent substantial further opening movement of said blast valve uponcompletion of an operating stroke by said motor.

2. In combination, a blast valve of the balanced type, means urging saidblast valve toward closed position, a fluid motor having a pistonmovable independently of said blast valve and engageable with a part ofsaid blast valve to move said blast valve from a closed to a partiallyopened position, means including a control valve for supplying pressurefluid to said fluid motor to cause operation thereof, restraining meansincluding a restraining piston arranged to move with said blast valve,and means for supplying pressure fluid to a surface of said restrainingpiston coincident with the operation of said fluid motor, the pressurefluid supplied to said piston acting in opposition to the pressure fluidsupplied to said motor whereby to prevent movement of said blast valveto its fully opened position.

3. In combination, a blast valve of the balanced type, means urging saidblast valve toward closed position, a fluid motor movable independ entlyof said blast valve and engageable therewith for moving said blast valvefrom a closed to partially opened position, means including a controlvalve for supplying pressure fluid to said motor to cause operationthereof, restraining means including a piston arranged to move with saidblast valve, and means responsive to operation of said control valve forsupplying pressure fluid to a surface of said piston before completionof an operating stroke by said fluid motor, the pressure fluid suppliedto said piston acting in opposition to the pressure fluid supplied tosaid motor whereby to prevent movement of said blast valve to its fullyopened position.

l. In combination, a blast valve of the calanced type, means urging saidblast valve toward closed position, a fluid motor having an operatingstroke less than the full operating stroke of said blast valve, saidmotor being movable independently of said blast valve and beingengageable therewith to move said blast valve from a closed to apartially opened position, restraining means including a piston arrangedto move with said blast valve, and means including a control valve forsupplying pressure fluid to said fluid motor and to a surface of saidpiston to cause operation of said fluid motor and movement of said blastvalve to a partially opened position, the pressure fluid supplied tosaid piston acting in opposition to the pressure fluid supplied to saidmotor whereby to prevent movement of said blast valve to its fullyopened position.

5. In combination, a blast valve of the balanced type, means urging saidblast valve toward closed position, a fluid motor having an operatingstroke less than the full operating stroke of said. blast valve, saidmotor being movable independently of said blast valve and beingengageable therewith to move said blast valve from a closed to apartially opened position, restraining means includin a piston arrangedto move with said blast valve, and means for supplying pro. sure fluidto a surface of said piston in response to the opening of said blastvalve, the pressure fluid supplied to said piston acting in oppositionto the action of said fluid motor whereby to prevent movement of saidblast valve to its fully opened position.

6. in combination, a blast valve of the balanced type, means urging saidblast valve toward closed position, a fluid motor for moving said blastvalve from a closed to a partially opened position, restraining meansincluding a piston arranged to move with said blast valve, saidrestraining means being arranged to oppose opening of said blast valve,and means including a control valve for supplying pressure fluid to asurface oi": piston, means responsive to operation of said control valvefor supplying pressure fluid to said fluid motor, and means interposedbetween said control valve and said fluid motor for preventing theapplication of pressure to said fluid motor until after fluid pressurehas been supplied to said piston, said fluid motor being suilioientlystrong to move said blast valve to its partially opened position inopposition to said restraining means 7. I. combination, a blast valve ofthe balanced type, means urging said blast valve toward closed position,a fluid motor having an operating stroke less than the full travel ofsaid blast valve, motor being movable independently of said blast valveand being engageable with a part of said valve to move said blast valveto a partially opened position, restraining means including a pistonoperably related with said blast valve, and means for supplying opposingpressure fluid to s id motor and to said piston respectively, wherebythe action of said piston is in opposition to the action of said motor,said motor being sufficiently strong to overcome the restraining actionof said piston throughout the full working stroke of said motor.

8. An operating system for a high voltage gas blast circuit breakercomprising, a biased closed blast valve, a first fluid motor operablyrelated with said blast valve and arranged to impart full openingmovement thereto, means including a breaker opening control valve forsupplying pressure fluid to said first motor to cause opening of saidblast valve, a second fluid motor operably related with said blast valveand arranged to move said blast valve to a partially opened position,means including a breaker closing control valve for supplying pressurefluid to said second motor to cause blast valve opening movementthereof, restraining means including a piston operably related with saidblast valve, said restraining means being arranged to oppose openingmovement 01" said blast valve, and means for supplying pressure fluid tosaid piston in opposition to the pressure fluid supplied to said secondmotor and in response to opening of said breaker closing control valve,said piston being effective to prevent opening movement of said blastvalve after said blast valve is moved to its partially opened positionby said second fluid motor.

9. An operating system for a high voltage gas blast circuit breakerhaving an interrupting contact and an isolating contact, a blast valveof the balanced type, means urging said blast valve toward closedposition, fluid actuated means for imparting circuit closing movement tosaid isolating contact, a fluid motor having an operating stroke lessthan the full travel of said blast valve, said motor being engageablewith a part of said blast valve to move said blast valve from a closedto a partially opened position, restraining means including a pistonoperably related with said valve, and means including a closing controlvalve for supplying pressure gas to said fluid actuated means, and meanseffective after opening or said closing control valve for supplyingopposing pressure gas to said motor and to said piston respectively,whereby the action of said piston is in opposition to the action of saidmotor, said motor being sufficiently strong to overcome therestrainingaction of said piston throughout the full working stroke of said motor,said piston being effective to prevent substantial further opening ofsaid blast valve after completion of the working stroke of said motor.

10. An operating system for a high voltage gas blast circuit breakerhaving an interrupting contact and an isolating contact, a blast valveof the balanced type arranged to supply a blast of gas to said contacts,means urging said blast valve toward closed position, fluid actuatedmeans for imparting circuit closing movement to said isolating contact,a fluid motor having an operating stroke less than the full travel ofsaid blast valve, said motor being engageable with a part of said blastvalve to move said blast valve from a closed to a partially openedposition, restraining means including a piston operably related withsaid blast valve, means including a closing control valve for supplyingpressure gas to said fluid actuated means, means responsive to openingof said closing control valve for supplying pressure gas to said piston,and means responsive to operation of said fluid actuated means forsupplying pressure gas to said motor, the pressure gas supplied to saidpiston acting in opposition to the pressure gas supplied to said motorwhereby the action of said piston is in opposition to the action of saidmotor, said motor being sufficiently strong to overcome the restrainingaction of said piston throughout the full working stroke of said motorand said piston being effective to prevent substantial further openingof said blast valve after completion of the Working stroke of saidmotor.

11. An operating system for a high voltage gas blast circuit breakerhaving an interrupting contact and an isolating contact, a blast valvearranged to supply a blast of gas to said contacts, means urging saidblast valve toward closed position, fluid actuated means for impartingcircuit closing movement to said isolating contact, a fluid motor havingan operating stroke less than the full travel of said blast valve, saidmotor being engageable with a part of said blast valve to move saidblast valve from a closed to a partially opened position, restrainingmeans including a piston arranged to move with said blast valve, meansincluding a closing control valve for supplying pressure gasto saidfluid actuated means, and means responsive to operation of said fluidactuated means for supplying opposing pressure gas to said motor and tosaid piston respectively, whereby the action of said piston is inopposition to the action of said motor, said motor being sufficientlystrong to overcome the restraining action of said piston throughout thefull working stroke of said motor and said piston being effective toprevent substantial further opening of said blast valve after completionof the Working stroke of said motor.

12. An operating system for a high voltage gas blast circuit breakerhaving an interrupting contact and an isolating contact, a blast valvearranged to control the supply of pressure gas to said contacts, meansurging said blast valve toward closed position, fluid actuated means forimparting circuit closing movement to said isolating contact, a fluidmotor having an operating stroke less than the full travel of said blastvalve, said motor being engageable with a part of said blast valve tomove said blast valve from a closed to a partially opened position,restraining means including a piston arranged to move with said blastvalve, means including a closing control valve for supplying pressuregas to said fluid actuated means, means effective after opening of saidclosing control valve for supplying pressure gas to said motor and meansresponsive to opening of said blast valve for supplying pressure gas tosaid piston, the pressure gas supplied to said piston acting inopposition to the pressure gas supplied to said motor whereby the actionof said piston is in opposition to the action of said motor,

10 said motor being sufliciently strong to overcome the restrainingaction of said piston throughout the full working stroke of said motorand said piston being effective to prevent substantial further openingof said blast valve after completion of the working stroke of saidmotor.

13. An operating system for a high voltage gas blast circuit breakerhaving an interrupting contact and an isolating contact, a blast valvearranged to supply a blast of gas to said contacts, means urging saidblast valve toward closed position, a fluid motor having an operatingstroke less than the full travel of said blast valve, said motor beingengageable with a part of said blast valve to move said blast valve froma closed to a partially opened position, restraining means including apiston operably related with said valve, and means effective afteropening of said closing control valve for supplying opposing pressuregas to said motor and to said piston respectively, whereby the action ofsaid piston is in opposition to the action of said motor, said motorbeing sumciently strong to overcome the restraining action of saidpiston throughout the full working stroke of said motor and said pistonbeing effective to prevent substantial further opening of said blastvalve after completion of the working stroke of said motor.

1a. An operating system for a high voltage gas blast circuit breakerhaving an interrupting contact and an isolating contact arranged inseries, a blast valve of the balanced type arranged to supply a blast ofgas to said contacts, means urging said blast valve toward closedposition, fluid actuated means for imparting circuit closing movement tosaid isolating contact, a fluid motor having an operating stroke lessthan the full travel of said blast valve, said motor being engageablewith a part of said blast valve to move said blast valve to a partiallyopened position, restraining means including a piston moveable with saidvalve and arranged to oppose opening movement thereof, means including aclosing control valve for supplying pressure gas to said fluid actuatedmeans, and means effective after opening of said closing control valvefor supplying opposing pressure gas to said motor and to said pistonrespectively.

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